Flexible seam joint for use in robotic skin

ABSTRACT

An artificial skin such as an outer covering or skin for an animatronic character. The skin may be formed by a method that includes providing a mold assembly with an exterior mold and a core. In the mold assembly, a cavity is formed between inner surfaces of the exterior mold and exterior surfaces of the core that defines the skin system. The mold assembly includes a seam-forming wall extending between the inner and exterior surfaces. The method includes inserting an elongate, tubular guide through holes in the seam-forming wall and pouring an elastomeric material into the mold to occupy the cavity between the exterior mold and the interior core. The method includes, after the material has hardened, cutting a seam in the skin system by cutting the material along the seam-forming wall. The tubular guide is separated into guide segments and a staggered joint is formed at the cut seam.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. patent application Ser. No.12/970,641, filed on Dec. 16, 2010, entitled “FLEXIBLE SEAM JOINT FORUSE IN ROBOTIC SKIN,” which is hereby incorporated in its entirety byreference.

FIELD OF THE INVENTION

The present description relates, in general, to creating realistic skinfor robots or for use with robotics or other applications in which skinor similar coverings are applied (e.g., robotics used to simulatemovement of a human's or a character's face, hands, or the like), and,more particularly, to a skin or artificial skin system with a flexiblejoint adapted for joining two sides of a seam in the skin and to amethod of forming such a joint in a skin.

RELEVANT BACKGROUND

Durable materials that are often also flexible and elastic such asplastics and rubbers are used in many applications to create coveringsor skins that are applied over an internal physical support structure orskeleton. For example, artificial skins or skin systems are used tocreate realistic models of humans, animals, and characters, and, whencombined with robotics, such models may accurately simulate live beings.

Robotics involves the design and use of robots to provide programmableactuators or drivers to perform tasks without human intervention, andthere have been significant demands for robotic devices (or robots asthese terms may be used interchangeably) that simulate humans, animals,and other living beings or characters. These robotic characters arerelied upon heavily in the entertainment industry to provide specialeffects for movies and television and to provide robots for use in showsand displays in amusement or theme parks. For example, robotics may beused to provide a character in a theme park ride or show that repeats aparticular set of movements or actions (e.g., programmed tasks) based onthe presence of guests or a ride vehicle or another triggering event.

It is likely that the interest in robotics will continue to expand inthe coming years, and a growing area of interest is how to providerobots that appear more realistic. Many robotics companies have focusedon creating robots with software, processing hardware, and mechanicalactuators or drivers that allow the robots to behave more like thenatural creature that is being simulated. Much work has been done tocreate robots that can move and even behave similar to humans such as bymanipulating objects with mechanical assemblies that behave like handsconfigured to be human-like. Significant effort has also been directedto providing robots with realistic facial animation such as having arobot open and close its mouth to provide lip synchronization withoutput audio (e.g., with speech) and by providing particular facialmovements including eye movement such as frowning, smiling, and thelike.

While many advances have been made in realistically simulating thephysical movement and facial movement of a character, problems withmaintaining a realistic or desired movement or facial animation stilloccur when the robotics (e.g., internal components of a robot includingmechanical/structural portions as well as software, hardware, powersystems, and the like) are covered with a skin or skin system, and therealism of the robotic figure or character may be furthered or hinderedby the movements of the skin. For example, a robot used to simulate aparticular creature would be covered with skin or a covering assembly toimitate the natural or desired covering for the creature such as skinand fur/hair for many creatures, clothes for some creatures such ashumans or characters (e.g., characters from animated films or televisionor puppets), or more fanciful covering system such as a metallic suit orany other desired covering.

In simulating humans or human-like characters, the robotics aretypically covered in a skin that is fabricated of flexible material tomove naturally with the underlying robotics. The skin may be formed of arubber material or a silicone that is attached or anchored to themechanical actuators or drivers of the robotic system, and the skin isconfigured to have an outward appearance similar to the character orcreature being simulated by the robot. For example, the facial skins canbe formed so as to have an uncanny resemblance to the character (orperson) they are imitating, but often this resemblance ends when theattached robotics begin animating the face. The skin typically is of asingle material with one set of physical characteristics such ashardness, flexibility, and the like.

To initially assemble and then later maintain the robotics, the skin orskin system typically will include at least one seam where two portionsor sides of the skin are joined together. In providing such a joint inthe skin, it is desirable for the joint to be durable and lasting, forthe joint to allow repeated use (e.g., opening and closing/mating of thejoint) to allow the skin to be applied and removed numerous times, andfor the joint to facilitate or at least not hinder realistic movement ofthe nearby skin or covered robotic components. For example, in ahuman-like character, a seam that has to be joined may be provided onthe back of the neck so as to allow application and removal of a skinsystem over a robotic head. The robotics may require periodicmaintenance such that the skin may be removed numerous times over thelife of the robotic character. However, it is also very important forthe joint on the neck to be formed so as to limit any interference orbinding of the overall skin system that may be seen in the face, ears,top of the head, or front portion of the neck as this may spoil orreduce the realistic movement of the skin.

Presently, a number of join techniques are used in fabricating skinsystems for robotics and other applications. One approach is to bond thetwo sides of the seam together such as by applying adhesive to two flatabutting sides after the skin is positioned over the robotic assembly orfeature. Bonding can provide a relatively flexible joint, but it istypically undesirable as it can come apart over time and, moresignificantly, does not allow for opening and closing for access to thecovered components. Stitching is sometimes used for joining a seam inskin, and a stitched seam provides some amount of stretching andtwisting. But, stitched seams are typically not very durable as thestitching material quickly tears at the stitching holes with movement ofthe underlying robotics, causing the joint to fail over time.

In many skin systems, a conventional zipper is bonded into the seamduring the molding process for a skin system, and then after applicationof the skin system, the zipper is used to open and close the seam of theskin system (such as for the back of a head or a wrist of a humanrobotic character). Zippers provide a strong and reusable joint.However, there are a number of problems with the use of zippers in manyapplications where realistic skin movement is required or desired.Fabrication can be time-consuming and difficult as the fabricator has tofully clean up the zipper to remove all skin material from its teeth andworking parts to allow the zipper to work properly. The zipper is aforeign material or body that has to be molded into the skin, which isnot sympathetic to the movement of the adjoining flexible skin material.As a result, the zipper may tend to tear out of the seam over time andrepeated use. Further, zippers are a single body or member that tends tomove as a unit such that the skin in the area near to the zipper maymove in an unnatural or undesirable manner, e.g., a zipper in the backof a neck may move as a block with such movements being propagated tothe front neck skin and facial features causing them to twist or pull ina non-realistic manner. Zippers typically are not flexible or pliable(e.g., readily able to stretch or “stretchy”) so that, in addition tomoving as a unit, the zippers can cause unnatural looking movement inadjoining areas of the skin.

Hence, there remains a need for improved methods for fabricating skinsystems or simply “skins” for robotics and other applications thatinvolve covering a support structure with a covering or skin. Preferablysuch methods would be inexpensive and relatively simple to carry out andwould provide a joint for a seam in the skin that is flexible (e.g.,move more naturally with the adjoining skin material) and also durable.

SUMMARY OF THE INVENTION

The present description addressed the above and other problems byproviding a skin (and methods of making such artificial skin) that isuseful for covering robotic mechanisms so as to allow ready access tothe mechanisms. To this end, the skin includes a staggered joint made upof a number of peaks and valleys or tongue and groove joints. Thisjoint, which is integrally formed with adjoining skin portions/sides ofthe seam, is formed through the use of a seam-forming wall provided on asurface of the molding assembly used during the pouring process for theskin.

In one case, the wall takes a repeating S-shaped pattern from end to endand extends up from an outer surface of the mold core (e.g., on asurface used to define a back of a neck when the robotic mechanism orassembly is used to provide a robotic head). Such a series of rounded orcurved peaks and valleys (or tongues and grooves) may readily be joinedand separated to allow application and removal of the skin to a roboticdevice but yet moves naturally with the surrounding skin and is verydurable (less likely to tear or to have foreign materials work their wayout of the moving skin system). Once closed or coupled, the joint may beretained in the closed position or state through the use of an elongateretaining member (e.g., a flexible fiberglass rod or the like) that isextended through the protruding peak elements or tongues via wearresistant guide segments provided in each of these elements/tongues suchas via a tubular guide that is positioned in the mold assembly so as toextend through the accordion folds of the seam-forming wall prior to thepouring of elastomeric material to create the skin system.

More particularly, a method is provided for fabricating a product, suchas a robot head, with an artificial skin system. The method includesproviding a mold assembly with an exterior mold and an interior core. Inthe mold assembly, a cavity is formed between inner surfaces of theexterior mold and exterior surfaces of the interior core that defines afinal shape of the skin system. The mold assembly includes aseam-forming wall extending between the inner and exterior surfaces. Themethod also includes inserting an elongate, tubular guide through aseries of holes in the seam-forming wall and then pouring an elastomericmaterial (such as rubber, polyurethane, or the like) for the skin systeminto the mold to occupy the cavity between the exterior mold and theinterior core. The method also includes, after the material has hardenedto form the skin system, cutting a seam in the skin system by cuttingthe material along the seam-forming wall. During such cutting, thetubular guide is separated into a plurality of guide segments and astaggered joint is formed at the cut seam.

In some embodiments, the method includes removing the skin system fromthe mold assembly, applying the skin system over a robotic assembly withthe staggered joint in an at least partially open state, placing sidesof the seam together to place the staggered joint in a closed state, andinserting a flexible retaining member through the guide segments. Insuch cases, the tubular guide may be a tube of rigid material and theretaining member may be a flexible rod extending the length of the cutseam.

In some implementations of the method, the seam-forming wall follows orincludes a pattern of repeating S-shapes from a first to a second end.In the method, the seam-forming wall may be configured to define aplurality of alternating tongues and grooves in each side of the cutseam, whereby the staggered joint comprises a plurality of tongue andgroove joints. In such cases, each of the sides of the seam includes atleast two of the tongues and two of the grooves and one of the guidesegments is embedded in each of the tongues. In one exemplaryimplementation, the material used for the skin system is a rubber orpolyurethane, and the method further includes inserting a flexible rodthrough the guide segments with the seam in a closed state, whereby thestaggered joint is retained in a closed state and is concurrentlyallowed to move with adjoining portions of the skin system in two ormore directions.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a mold assembly for use in forming a skin or skinsystem with a flexible staggered joint as described herein, and the moldassembly is shown with a front half of an exterior mold in position on abase and a rear half removed to expose a portion of a mold core or innersupport structure that includes a seam-forming portion of the core(although these seam-forming components could also be provided on aninner surface or wall of the exterior skin mold in some embodiments);

FIG. 2 is a partial end view of the core or inner support structure ofFIG. 1 with the flexible guide removed showing more detail ofseam-forming wall (e.g., recurring S-shaped wall used to form pluralityof side-by-side tongues and grooves (or a “stacked” tongue and groovejoint));

FIG. 3 is a partial view of a skin or skin system during the fabricationprocess specifically showing the skin after removal of the exterior moldand during cutting of the skin along the seam-forming wall (includingcutting the flexible guide into a plurality of guide segments) toprovide the flexible seam in the skin;

FIG. 4 is another view of the skin or skin system of FIG. 3 shown at alater stage in the fabrication process after the flexible seam has beencut to allow removal of the skin from the core showing a resulting seamproviding an integral joint made up of a plurality of tongue and grooves(or a repeating S-shaped pattern);

FIG. 5 illustrates a robotic figure with a robotic assembly (e.g., ahead and neck) and a skin system of the present description covering therobotic assembly illustrating the inclusion of a retaining rod in theflexible guide segments within the plurality of tongues of the tongueand groove joint; and

FIG. 6 is a flow diagram for a process or method of fabricating a skinand applying the skin to a robotic assembly or component such as awrist, a head/neck, or the like.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Briefly, the following description is directed toward skin systems or,more simply, skins such as a unitary exterior skin layer for applicationover a robotic device (e.g., a robotic head, robotic-based hands andarms, and so on) and to methods of fabricating such skins or skinsystems. It was recognized that there is a need for providing a seam insuch skins that allows a skin to be applied to the robotic device byexpanding its size temporarily and that then can be sealed together or“joined” to close the seam. In the past, these seams typically werejoined using zippers that caused the skin to move in an unnatural mannerand that typically failed over time.

In response to these and other issues, the following describes a seamwith an integrally formed joint that closes or joins the seam in theskin with a staggered manner. The skin joint taught herein may bethought of as a joint assembly with a plurality of tongue and groovejoints that allows two mating sides of the joined skin at the seam to bereadily separated and then re-coupled together. In each tongue of thejoint assembly, a tubular guide is provided such that, when all thetongues are positioned in corresponding or mating grooves to join theskin at the seam, an elongate retaining member (a flexible rod or thelike) may be extended through all the guides to retain the tongueswithin the grooves (e.g., to retain the joint assembly in the coupled orclosed position while allowing some amount of stretching, twisting, andother movement).

The staggered joint allows for natural movement in all directions. It isdurable and easy to use. The joint can be used as a better and morerobust alternative to zippers and other existing seam joiningtechniques. The staggered joint requires about the same amount of labor,if not less, to pour around a seam-forming wall provided in the mold (onthe exterior surface of an inner core or inner surface of an exteriormold component) as pouring about a zipper. The staggered joint may beused to join a seam on a neck for a skin used to cover a robotic headand other skins used to cover robotics. In the case of human orhuman-like robotics, the staggered joint may be used on wrists, backs ofarms, legs, and so on. The skin joined together with the staggered jointacts or moves as if the joined seam is not even there as the joint doesnot noticeably restrict movement of the skin.

FIG. 1 illustrates a mold assembly 110 for use in forming a skin or skinsystem (not shown in FIG. 1) with a pour of flexible, compressible, andresilient material such as a rubber or a compound useful in forminglife-like skins. As discussed above, the formed skin has a seam with anintegral staggered joint or joint assembly, and the mold assembly 110includes a seam forming assembly (or set of components) 130 to provide astaggered joint (or joint assembly with a plurality of tongue and groovejoints) upon a pour using the mold assembly 110.

The mold assembly 110, in this example, is configured for use in forminga skin for covering a robotic head and to provide a seam with a reusablejoint along a rear portion of the neck. The mold assembly 110 is shownto include a base or platform 112 and a core or inner mold component 114is mounted onto the base 112. A front half 116 of an exterior moldassembly is also positioned on the base 112, with a rear half removed ornot shown to expose the features of the seam forming assembly 130 andcore 114. The core 114 has a rear neck surface or sidewall 120 thatextends upward from the base 112 to an upper skull surface 122 with aridge 123. The depth of the ridge 123 along with the spacing of theinner surfaces of the exterior mold away from the neck surface 120 (amold offset distance) define a thickness, t_(Skin), of a skin formedwith the mold assembly 110. The skin thickness, t_(Skin), may vary topractice the invention but typically will range from about 1/16 to about¼ inches depending upon the materials used for the skin and its intendeduses.

Significantly, the mold assembly 110 includes a seam-forming assembly130 that is configured for forming a staggered joint in a seam in theskin formed with the mold assembly 110. As shown, the seam-formingassembly 130 includes a seam-forming wall 132 that extends outward fromneck surface 120 of core 114 as shown in FIG. 2 such that the seam orjoint has a height or distance, D_(Joint), that is equal to thethickness of the skin, t_(Skin). The wall 132 extends from a first end134 adjacent or abutting the base 112 to a second end 135 adjacent orabutting the skullcap (or upper skin edge-defining) edge or ridge 123.In this manner, the wall 132 defines a seam or seam with an integraljoint that has a particular length, L_(Joint/Seam), that is chosen tofacilitate ready application and removal of the skin system over aparticular robotic device, and the length, L_(Joint/Seam), typicallywill be larger for larger robotic devices (e.g., a length of 8 to 12inches for a full size human head device and 3 to 6 inches for a fullsize human wrist or the like). However, the particular length of thejoint is not limiting to the invention and neither is the thickness ofthe skin and associated seam/joint.

The wall 132 is not merely linear between the ends 134, 135 but,instead, is arranged in a zigzag pattern (or repeating S-shapedpattern). This pattern has a width between peaks and valleys (or tonguesand grooves) that defines a resulting width, W_(Joint), of the jointformed based on wall 132. Each repeated cycle or pattern creates twotongues and two grooves, with one tongue projecting in one direction andone tongue projecting in a second, opposite direction. Such anaccordioned wall 132, thereby, defines a plurality of tongue and grooveshapes that will be formed in the skin using mold assembly 110. The wall132 may have a thickness that is great enough to define a seam or gapbetween the two sides or portions of the skin on either side of the wall132 after pouring of skin material into the mold assembly 110 (e.g., tofacilitate cutting or separation of the two skin portions or sides ofthe seam). The number (or density) of the tongue and groove joints inthe seam may also be varied to practice the invention with 1 to 3 perinch being useful in some cases. The wall 132 typically is formed of thesame rigid material as the core (e.g., a hard plastic or the like), andthe wall 132 may be affixed to the neck surface 120.

According to another useful aspect of the invention, the mold assembly110 is shown to include a guide member 140. The guide member 140 is usedupon formation of the skin to provide a plurality of guide segments inthe tongues that are used to guide a retaining member through thetongues and to provide wear-bearing surfaces in the skin material (e.g.,to avoid tearing and the like)). The guide member 140 may take the formof a rigid, elongate tube such as a tube formed of abrasion resistantmaterial that is very durable such as a peroxide-cured silicon tube(such as Versilic™ Silicone Tubing available from Saint-GobainPerformance Plastics (e.g., Formulation SPX-50) or other distributors)or the like. The guide member 140 in seam-forming assembly 130 isextended from a first end 142 through holes 136 in the wall 132 to asecond end 145. To avoid the tubular guide member 140 being filled withskin material during a pouring operation, a plug 143 is provided on thebase 112 at the first end 142 and a plug 144 is provided on ridge/edge123 at the second end 145.

FIG. 2 illustrates the wall 132 from an end view (such as from the base112) with the tubular guide member 140 removed. As shown, the sidewall132 includes the holes 136 that each has a diameter, D_(Hole), that istypically slightly larger than the outer diameter of the tubular guide140. Further, the holes 136 are spaced above the neck surface 120 of thecore 114 a distance, H_(Gap), (such as one fifth to one fourth or moreof the wall height, D_(Joint)) to define a height of a gap so as toembed the guide member 140 within the tongues of the skin to betterretain each segment of the guide member 140 within a tongue during useof the skin. Likewise, the holes 136 are spaced apart from the top edgesor sides of the wall 132 to position the holes 136 more centrally withinthe wall 132.

During use, the guide member 140, as shown in FIG. 1, is pushed orthreaded through the holes 136 in wall 132 to mate with the plug 144 inedge 123, and, then, the core 114 with guide member 140 is placed on thebase 110, which plugs end 142 with plug 143. The back or rear portion ofthe exterior skin mold may then be mated with base 112 and front portion116 and the skin material poured into the gap provided about the innercore 114, which defines the shape and thickness of the skin as well asprovides skin material that contacts the surfaces of the wall 132 andencapsulates the guide member 140.

FIGS. 3 and 4 illustrate a partial view of a skin or skin system 310during an exemplary fabrication process of the present description.Specifically, the skin 310 is shown still on the core 114 but afterremoval of a rear or back exterior mold component. To create thestaggered joint or seam 320 with integral tongue and groove joints, acutting tool or knife 305 is shown in FIG. 3 being used to cut along thesides or surfaces of the seam-forming wall 132. This cutting operationcuts through the thickness, t_(Skin), of the skin to form the joint 320between a first portion or side 312 of the skin 310 and a second portionor side 314 of the skin 310. FIG. 4 illustrates the skin 310 after thecutting of the joint/seam 320 is completed to show how the joint/seam320 allows the skin 310 to be removed from the core 114 and, then,applied to a robotic device (as shown in FIG. 5).

As shown, the skin 310 includes a joint 320 that is formed of aplurality of tongue and groove joints with each side 312, 314 includingalternating tongue and groove pairs. For example, the joint 320 isprovided in part with a tongue 322 and groove 324 pair on first side 312of skin 310. The tongue 322 has a body with a height, H_(Tongue), thatis equal to or about equal to the width, W_(Joint), of the joint 320,and the body of the tongue 322 has a shape defined by a sidewall 323(which was defined in shape and configuration by the seam-formingsidewall 132). The groove 324 is defined by a sidewall 325 (which isdefined in shape and configuration by the seam-forming sidewall 132) toprovide a recess or valley in the side 312 that has the same shape andsize as a tongue 322 so as to be able to receive such a tongue such asone on side 314 with a shape like tongue 322. The groove 324 has adepth, D_(Groove), that equals (or nearly equals) the width, W_(Joint),of the joint 320 as well as the height, H_(Tongue), of a tongue (such astongue 322) and has a width, W_(Groove), similar to or matching (e.g.,slightly larger) than the width of the tongues, W_(Tongue). Likewise,the side or portion 314 of the skin 310 that mates or couples with theportion or side 312 has alternating tongues and grooves such as tongue332 defined by sidewall 333 and groove 334 defined by sidewall 335.

As discussed above, the skin 310 includes the tubular guide 140 due toits insertion into the sidewall 132 of core 114 prior to the pouring ormold fill step of skin fabrication. The cutting with tool or knife 305along the sidewall 132 cuts skin material but also cuts the guide 140into a plurality of segments 341. Each of these segments 341 is retainedor encapsulated within each of the tongues 322, 332 such that eachtongue 322, 332 includes a guide for a retaining member or element (suchas member 520 shown in FIG. 5). When the joint is closed with thetongues inserted into corresponding or mating grooves in the two sides312, 314, the segments 341 become generally aligned to facilitateinsertion of the retaining member or element. In this manner, too, eachsegment 341 typically has a length that is equal to the width,W_(Tongue), of the tongue in which it is embedded. The segments 341 aswell as the tongues and grooves of the joint 320 may be thought of asbeing integrally formed with the skin 310 as part of the skin molding orformation process, which allows each of these components of the joint tobe more wear resistant, to move more sympathetically or naturally withthe skin portions 312, 314, and to be retained within the skin 310 overtime rather than tearing away as is common with foreignbodies/materials.

FIG. 5 illustrates an assembled (or partially assembled) robotic device510 with a robotic assembly/mechanism 512 that has been covered (orpartially covered/encased) with the skin or skin system 310. The device510, in this non-limiting example, is a head and neck assembly and theskin 310 provides a unitary skin that fits over the face and neck of thedevice 510. As shown, the seam 320 has been closed with the sides 312and 314 placed in adjacent and abutting or nearly abutting contact. Inthis position, the tongues 322, 332 have been inserted into receiving ormating grooves such as grooves 324, 334 (i.e., at least one tongue 322from side 312 is inserted into a groove on side 314 and at least onetongue 332 from side 314 is inserted into a groove on side 312 to formthe closed joint 320).

As shown, the joint 320 in skin 310 may be thought of as a staggeredjoint or a joint assembly made up of plurality of tongue and groovejoints that alternate in their orientation (i.e., a tongue, groove,tongue, groove, and so on pattern on side 312 and a groove, tongue,groove, tongue, and so on pattern on side 314). The tongues and groovesdo not run the length, L_(Joint), of the joint 320 but instead extendthe depth of the joint or skin thickness, t_(Skin) (into the paper ofFIG. 5). Instead of (or in addition to) the tongue and groovedescription, the joint 320 may be thought of as a staggered join of thesides 312, 314 provided by a repeating pattern of alternating peaks andvalleys as may be provided with a repeating S-shaped pattern.

The peaks and valleys (or tongues and grooves) may have nearly any shapeto practice the invention such as rectangular, triangular, or the like.However, in some cases, a rounded tongue body or tip is desirable suchthat the valleys/groove bottoms or bases are rounded. Rounded surfacesare useful in skin systems (such as a pattern of equidistant curves)because sharp corners and valleys can lead to tears in the elasticmaterial (such as silicone) used for skin as the skin moves with theunderlying or covered robotic mechanisms. The joint 320 is designed toallow a movement in nearly any direction as is shown with arrow 550indicating stretching and compression along the length of orlongitudinal axis of the joint 320 and with arrow 552 indicating atwisting movement about the axis of the joint 320 or even a side to sidemovement at a point along the length of the joint 320. The joint 320 istypically hidden from view of observers of the device 510 such that itis allowable and even useful in some senses (such as to facilitatemovements) to allow some gapping or spreading of the two sides 312, 314at the joint 320.

However, it is also typically desirable to maintain the seam in a joinedarrangement or to “lock” the joint in a closed or coupled position withthe tongues of side 312 in grooves of side 314 and vice versa. To thisend, a retaining member or element 520 is included in the device 510 andextends through the guide segments 341 in adjacent tongues 322, 332. Theend 522 of the retaining member 520 may be fastened to the roboticassembly/mechanism at anchor 514 (such as with a hook and eyearrangement or the like). With the retaining member or element 520installed in guide assembly 140, the joint 320 is able to stretch andtwist 550, 552 but adjacent pairs of the tongues 322, 332 are maintainedin a proximate and often abutting arrangement (and a tongue is keptwithin its receiving or mating groove). The retaining member 520 isgenerally a unitary component and is flexible (not rigid). For example,the member 520 may be a flexible cable or rod formed of a plastic orsimilar material (e.g., a fiberglass rod) or a metal (such as a wirecable/rope or the like).

FIG. 6 illustrates a flow diagram for a method 600 of fabricating a skinor skin system with a staggered joint that is integral or unitarilyformed with the skin. The method 600 starts at 605 such as with thedesign of a robotic mechanism that requires a skin covering and then thecreating of a mold assembly (including sculpting or other processes)that defines the shape and thickness of the skin. At 610, the process600 includes providing a core or inner skin support component of themold assembly, and the core includes a wall extending up from one of itssurfaces (or down from an inner surface of an exterior mold component insome embodiments). This wall defines the pattern of a staggered joint,and the wall includes a pathway such as a series of holes/openings forreceiving a retaining member guide. At 620, the method 600 continueswith the insertion of a flexible guide into the wall through theseholes/openings. Step 620 may also include plugging or capping the endsof the tubular guide to avoid skin material entering and plugging up theinner chamber or lumen of the guide.

At 630, the skin mold assembly is completed and closed, which mayinclude positioning the inner core onto a base and enclosing the corewith two or more exterior mold or skin defining components. At step 640,the method 600 includes pouring skin material (such as a rubber thathardens to a desired hardness and provides a lifelike flexibility,stretchiness, and resilience) into the chamber defined between theexterior mold components and the inner core. In step 640, skin materialflows against the sides of the seam-forming wall and encases the guidemember. After the skin solidifies, at 650, all or a portion of theexterior mold is removed to expose the portion of the skin that includesseam/joint being formed with the wall on the core.

At 660, the method 600 continues with cutting through the skin along oneor both sides of the seam-forming wall to form the seam in the skin withan integral, staggered joint. Step 660 also includes concurrent withcutting the skin material cutting the elongate guide into a plurality ofsegments that are each retained in the protrusions or tongues of thestaggered joint. At step 670, the skin is removed from the core usingthe newly formed staggered joint (e.g., opening the joint). Some amountof clean up of the seam surfaces may be performed, but, in general, thecreation of the joint using the S-shaped or other-shaped wall is a quickand easy process that requires less labor than a conventional zipperedjoint (which requires all or nearly all skin material to be removed fromzipper teeth for proper performance).

At step 680, the skin with the staggered joint is applied to a roboticsassembly or mechanism to form a skin-covered robotic device. The method600 continues at 690 with closing the joint by interlacing pairs ofpeaks and valleys on the two sides of the formed joint (or matingappropriate tongues of skin on one side of the seam with associated orpaired grooves of skin on a second side of the seam). Step 690 alsoincludes inserting the flexible retaining member or element through theguide segments provided in the tongues or peak/protruding elements ofthe joint and, in some cases, affixing an end of the retaining member tothe robotics assembly/mechanism. At 695, the method 600 is ended orrepeated to create an additional skin at 610.

Typically, the components of the skin system will be elastic andflexible to allow manipulation by robotics. The material may be aplastic or, more typically a polyurethane or rubber. In someembodiments, the skin is formed of silicone such as a silicone foam or asilicone foam with additives such as a silicone and urethane foam. Theskin with integral, staggered joint is typically fabricated by a singlepour with the details of an original sculpt (that is used to create anexterior mold) to be picked up or created in outer surfaces of the skin.For example, a molding process may be followed in which fluid resin(e.g., a thermosetting, thermoplastic, or other resin with additivesprovided to cause the resin to solidify) is poured into a mold or frameinto which the core with seam-forming wall has been placed.Concurrently, the pouring of the skin causes the guide member or elementto become intrinsically bonded together (such as a crosslink or otherbond between the materials of the differing components) such that thelater formed guide segments are attached to the tongues/protrudingelements to behave as an integral unit or skin system.

Although the invention has been described and illustrated with a certaindegree of particularity, it is understood that the present disclosurehas been made only by way of example, and that numerous changes in thecombination and arrangement of parts can be resorted to by those skilledin the art without departing from the spirit and scope of the invention,as hereinafter claimed. The above examples have provided examples ofusing skin systems of the invention with robotics, but the skin orcovering systems of the invention are, of course, readily adaptable anduseful in other applications in which it is desirable to cover a stillor rigid frame or support structure or a dynamic or movable frame orsupport structure in a way that allows ready access to coveredcomponents with a seam. As a result, the use of the term “skin” is notintended as being limited to human or animal imitating robots, toys, ordevices, but it is instead to be inclusive of nearly any coveringassembly or layered overlay that may be applied to or used as a covering(typically, but not always, an external covering).

Further, the staggered joint such as joint 320 may be formed with amodified version of method 600. For example, some embodiments call forthe joint 320 (or staggered seam) to be formed without the use of aseam-forming wall in the core (or mold assembly). For example, themethod 600 may be modified by having step 610 involve simply providing acore without the wall. Then, the step of inserting the flexible guideinto the wall at 620 may be replaced by a step of providing the flexibleguide in the mold assembly cavity where a seam is desired (e.g., to bealigned so as to run the length or much of the length of a planned seamor joint).

The step of providing the tube or guide may involve suspending the tubewithin the cavity proximate or adjacent to the core. For example, theflexible guide may be suspended using bent wire inside the tub that canbe pulled out after the skin material hardens. The guide may be providedvia tack glue to post off of the mold core. In other cases, the guidemay be provided by pre-making/forming a strip of the skin-formingmaterial (e.g., a silicone strip) with a tube or flexible guide embeddedwithin it, and this strip may be placed within the cavity of the moldprior to pouring/filling the cavity.

With the guide embedded in the skin where the seam is to be formed, step660 of the method 600 may be modified to include cutting the skin,without use of the wall as a guide, to form the seam in a zigzag pattern(such as repeating S-shapes) including cutting the embedded guide intosegments (as discussed above). The cutting may be performed in many waysto practice the invention. For example, the staggered joint may be cutfreehand with a blade or a custom cutting tool. The joint (such as joint320) may be cut using a knife or cutting tool but using a preformedguide stencil, which could be made out of thick paper, plastic, or othermaterials. For example, a seam/joint pattern may be designed and adigital (e.g., a CAD) model formed of a stencil providing this pattern.The stencil may then be formed by printing it on a rapid prototypemachine. The staggered joint may also be cut in the skin using a custommade stamp or cookie cutter-type of tool that could be concurrentlypressed through the skin and the embedded guide to provide the skin orskin system shown in FIGS. 4 and 5.

We claim:
 1. An artificial skin formed of an elastomeric material,comprising: a sheet of the elastomeric material; a seam cut through thesheet of elastomeric material to separate a first side from a secondside of the seam; a first set of alternating tongues and grooves on anedge of the first side of the seam; a second set of alternating tonguesand grooves on an edge of the second side of the seam, the grooves ofthe second set being adapted for receiving the tongues of the first setand the tongues of the second set being adapted for being inserted intothe grooves of the first set; a plurality of guide segments, wherein oneguide segment is embedded within each of the tongues of the first andsecond sets of tongues and grooves, wherein each of the guide segmentshas a rigid tubular body with an exposed interior wear surface andwherein the rigid tubular body is supported by material of the tonguewith no other form of reinforcement in the tongue; and an elongate,flexible retaining member extending through the guide segments andcontacting the rigid tubular body of each of the guide segments about aperimeter of the exposed interior wear surface, when the first andsecond sides of the seam are positioned with the tongues and grooves ofthe first and second sets interlaced together.
 2. The skin of claim 1,wherein the first set of alternating tongues and grooves includes atleast two of the tongues and two of the grooves.
 3. The skin of claim 1,wherein the sheet of elastomeric material is formed by pouring a volumeof an elastomer into a cavity of a mold defining a unitary skin for arobotic assembly and in which a tube providing the guide segments ispositioned, whereby the guide segments and the tongues are integrallyformed.
 4. The skin of claim 3, wherein the mold includes a seam-formingwall with a zigzag pattern defining the first and second sets of thealternating tongues and grooves.
 5. The skin of claim 1, wherein each ofthe tongues has a body with a rounded tip and each of the groovescomprises a rounded valley for receiving one of the rounded tips.
 6. Theskin of claim 1, wherein the retaining member comprises a flexiblefiberglass rod.
 7. The skin of claim 1, wherein the tubular body of eachof the guide segments is formed of an abrasion-resistant material. 8.The skin of claim 1, wherein the tubular body of each of the guidesegments comprises a peroxide-cured silicon tube.
 9. An artificial skin,comprising: a sheet of elastomeric material; a seam cut through thesheet of elastomeric material to separate a first side from a secondside of the seam; a first set of alternating tongues and grooves on anedge of the first side of the seam; a second set of alternating tonguesand grooves on an edge of the second side of the seam, the grooves ofthe second set being adapted for receiving the tongues of the first setand the tongues of the second set being adapted for being inserted intothe grooves of the first set; and a plurality of tubular guide segments,wherein one of the tubular guide segments is embedded within each of thetongues of the first and second sets of tongues and grooves to providean integrally formed component with the elastomeric materialencapsulating an outer surface of the one of the tubular guide segments,wherein no additional element is provided in the elastomeric material toretain the one of the tubular guide segments within the artificial skin,and wherein each of the tubular guide segments is formed of a rigid andabrasion-resistant material.
 10. The skin of claim 9, further comprisingan elongate and flexible retaining member extending through the guidesegments when the first and second sides of the seam are positioned withthe tongues and grooves of the first and second sets interlacedtogether.
 11. The skin of claim 10, wherein the retaining membercomprises a flexible fiberglass rod.
 12. The skin of claim 10, whereineach of the tubular guide segments is integrally formed with one of thetongues such that an entire perimeter of an interior wear surfacereceives and abuts the retaining member.
 13. The skin of claim 9,wherein the first set of alternating tongues and grooves includes atleast two of the tongues and two of the grooves.
 14. The skin of claim9, wherein the sheet of elastomeric material is formed by pouring avolume of an elastomer into a cavity of a mold defining a unitary skinfor a robotic assembly.
 15. The skin of claim 14, wherein the moldincludes a seam-forming wall with a zigzag pattern defining the firstand second sets of the alternating tongues and grooves.
 16. The skin ofclaim 9, wherein each of the tongues has a body with a rounded tip andeach of the grooves comprises a rounded valley for receiving one of therounded tips.
 17. The skin of claim 8, wherein each of the tubular guidesegments comprises a length of peroxide-cured silicon tube.
 18. Anartificial skin, comprising: a sheet of elastomeric material; a seam inthe sheet separating a first side from a second side of the seam; afirst set of alternating tongues and grooves on an edge of the firstside of the seam; and a second set of alternating tongues and grooves onan edge of the second side of the seam, the grooves of the second setbeing adapted for receiving the tongues of the first set and the tonguesof the second set being adapted for being inserted into the grooves ofthe first set, wherein the first set of alternating tongues and groovesincludes at least two of the tongues and two of the grooves, furthercomprising a plurality of tubular guide segments embedded within each ofthe tongues of the first and second sets of tongues and grooves and anelongate and flexible retaining member extending through the guidesegments when the first and second sides of the seam are positioned withthe tongues and grooves of the first and second sets interlacedtogether, wherein the tubular body of each of the guide segments isrigid and is formed of an abrasion-resistant material, and wherein eachof the tubular guide segments is supported within the tongue in which itis embedded by the elastomeric material with no additionalreinforcements extending through the elastomeric material and about aperiphery of each of the guide segments.
 19. The skin of claim 18,wherein the sheet of elastomeric material is formed by pouring a volumeof an elastomer into a cavity of a mold defining a unitary skin for arobotic assembly.
 20. The skin of claim 19, wherein the mold includes aseam-forming wall with a zigzag pattern defining the first and secondsets of the alternating tongues and grooves.
 21. The skin of claim 18,wherein each of the tongues has a body with a rounded tip and each ofthe grooves comprises a rounded valley for receiving one of the roundedtips.
 22. The skin of claim 18, wherein the retaining member comprises aflexible fiberglass rod.
 23. The skin of claim 18, wherein each of thetubular guide segments comprises a length of peroxide-cured silicontube.
 24. The skin of claim 18, wherein each of the tubular guidesegments is integrally formed with the tongue in which it is embedded.25. The skin of claim 24, wherein each of the tubular guide segments isintegrally formed with one of the tongues such that an entire perimeterof an interior wear surface receives and abuts the retaining member.